With an increasing interest in, and need for, digital tools for personal and remote health monitoring (as the current pandemic has demonstrated), an innovative new digital fabric may soon be added to the growing list of health wearables that can be used to measure health metrics from the body’s surfaces.
Researchers at Massachusetts Institute of Technology (MIT) have designed the world’s first digital fabric fiber that contains digital devices which can sense, analyze and store health data, and use it to infer a person’s activity and state of health.
The digital fibers can be sewn into clothing to help monitor bodily functions.
So instead of looking at the watch on your wrist to check out your heart rate, you may soon have monitoring systems sewn right into the sleeves of your shirt.
The team behind the digital technology say this is the first example of an electronic fabric that can record digital rather than analog data (from a continuous electrical signal), which means it can be programmed like any other digital device.
As such, they say digital devices integrated into fibers could lead to fabrics with digital system capabilities for applications in physiological monitoring, human-computer interfaces and on-body machine-learning. This would generate exciting new possibilities for digital health applications.
The fiber contains tiny temperature sensors and memory devices aligned along its length.
The MIT researchers published a paper describing the digital fiber technology and its features in Nature Communications.
“This work presents the first realization of a fabric with the ability to store and process data digitally, adding a new information content dimension to textiles and allowing fabrics to be programmed literally,” said Yoel Fink, senior author on the study, in a news release from MIT. Dr. Fink is a professor in the departments of materials science and engineering and electrical engineering and computer science, and a principal investigator at the Research Laboratory of Electronics at MIT.
Fiber Embedded with Digital Chips
The fiber was created by placing hundreds of square silicon microscale digital chips into a preform that was used to create a flexible, polymer thread that was thin and flexible enough to be threaded into fabrics using a needle.
By precisely controlling the polymer flow, the researchers were able to create a fiber with continuous electrical connection between the chips over a length of tens of meters.
The researchers say this preform-to-fiber approach is scalable and can be used to produce tens of meters of flexible fiber containing hundreds of interspersed, digital temperature sensors and memory devices with a memory density of ~7.6 × 105 bits per meter.
The fibers can be washed at least ten times without breaking down.
“When you put it into a shirt, you can’t feel it at all,” said PhD student Gabriel Loke, one of the lead authors on the paper, in the MIT statement. “You wouldn’t know it was there.”
And when the digital fiber is incorporated within a shirt, it can collect and store body temperature data over multiple days. For example, the researchers found that the digital fiber was able to collect 270 minutes of body temperature data. They also took it a step further by incorporating some AI-based approaches, such as including a trained neural network with 1,650 neuronal connections stored within the fiber. This was used to analyze temperature changes, such as increases during physical activity and dips due to evaporation of sweat afterwards. Analysis of this data allowed for inference of the activity that the wearer was engaged in with 96 percent accuracy.
Digital Fabric: Fiber Design
The researchers had set out to create a fiber strand with distinct characteristics that include:
- Introducing digital components into a flexible polymeric fiber strand
- Overcoming the limitation of a single fiber containing a single device to allow for scalable multiplicity of distinct digital functions
- Enabling access to the device ensemble in the fiber through a single connection port at the fiber’s termination
- Enabling storage of the sensory input collected by to be stored in the fiber itself
- Storing a neural network trained to infer context from collected sensory data
The researchers say that because drawn fibers contain continuous domains, there is an opportunity to create uniform conductive buses connected to devices embedded along the entire length of a fiber.
Data Power and Application
A digital fiber can also store a great deal of information in memory. The researchers were able to write, store and read information on the fiber, including a 767-kB full-color short movie file and a 0.48 MB music file. The files can be stored for two months without power.
In the current design, the fiber is controlled by a small external device. Therefore, the next step will be to design a microcontroller chip that can be incorporated within the fiber itself. This would allow the system to operate as a full-fledged computer.
Loke said when they were dreaming up “crazy ideas” for the fiber, they thought about applications like a wedding gown that would store digital wedding music within the weave of its fabric, or even writing the story of the fiber’s creation into its components.
With respect to use as a digital health tool, the idea is that with the type of analytic power integrated in the digital fibers, they could one day sense and alert people in real-time to health changes like a respiratory decline or an irregular heartbeat, and store that data for weeks.
In addition, Loke believes the technology could also offer novel insights into human physiology. “This type of fabric could give quantity and quality open-source data for extracting out new body patterns that we did not know about before,” he said.